Dimmable incandescents, Halogen, Flourescents, HID Which way to go, which to go...

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Mule

Senior Member
Location
Oklahoma
We have a increasing amount of church clients that are wanting dimmable can lights in these ultra high ceiling sanctuary's. People do not like flourescents. With all of the shift away from incandescents with the Patriot Act, is there other cost effective ways to accomplish what the customer wants? Currently I have a customer that has a 3000 sqft sactuary with a 30ft ceiling and 20ft side walls and they want can lights :( We did another one recently with 250w halogens but we had alot of lamp failures due to the extreem heat. Any suggestions?
 

mivey

Senior Member
We have a increasing amount of church clients that are wanting dimmable can lights in these ultra high ceiling sanctuary's. People do not like flourescents. With all of the shift away from incandescents with the Patriot Act, is there other cost effective ways to accomplish what the customer wants? Currently I have a customer that has a 3000 sqft sactuary with a 30ft ceiling and 20ft side walls and they want can lights :( We did another one recently with 250w halogens but we had alot of lamp failures due to the extreem heat. Any suggestions?
Dimmable CFLs. Or dimmable T-8 fixture if you can talk them into a different kind of fixture.
 

Strife

Senior Member
They don't like the FL cans because they can't dim them? Or the cost associated with dimming them?
There's other ways to solve that. Our church did a ceiling remodel and the same issue came into play: FL: cheaper on energy, but huge initial cost to dim them. As the sanctuary needed about 100 cans, I suggested to combine them on 8 different switches where in some rows (in the front) every other 3rd would be able to be controlled separately and the back rows to have every other row on different switches. Took a little work to design all these combos, but everyone's pretty happy with the outcome.
Try to find what they want to accomplish, for instance they might have a screen where they want to dim he light near the screen. Leaving only 5 lights on out of 20 will accomplish same effect. Or they want to have the sanctuary dim, while the front is bright. Having the middle row on in the seating while the rest are off, and the front fully lit will accomplish again same effect as a dimming.
Another issue to consider is, keep in mind this: is not like the lights will be on 24/7, worst case scenario they'll probably run 20 hrs a week, which will not that big of a difference comparing to other places where lights are on for 20hrs a day. So that will not a big selling point with them (saving energy). In such places the biggest selling point is the huge amount of resources it takes to replace ONE LAMP. At 30' you pretty much need a lift, so if they really want to go incandescent I'd recommend to them investing money in a lift (one of those that goes over the benches). And also mention to them that unless they gonna have a trained maintenance person to change the lamps, it'll cost them quite a bit everytime they change a lamp.

You might wanna mention they have several colors nowadays for FL, some people might be against FL because they work all day in an office with 6K lamps and they hate it.

And last: HID is OUT OF THE QUESTION. Remember that HID don't come fully back on for about 15min after been turned off. At best they'll come back on after 2-3 minutes after being turned off.

We have a increasing amount of church clients that are wanting dimmable can lights in these ultra high ceiling sanctuary's. People do not like flourescents. With all of the shift away from incandescents with the Patriot Act, is there other cost effective ways to accomplish what the customer wants? Currently I have a customer that has a 3000 sqft sactuary with a 30ft ceiling and 20ft side walls and they want can lights :( We did another one recently with 250w halogens but we had alot of lamp failures due to the extreem heat. Any suggestions?
 
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dbuckley

Senior Member
Getting to be a regularly asked question in theatre too.

The real question is what they want of their dimming.

If they are looking for 0% - 100% dimmability with no bumps, with good color rendering, then incandescent is the only realistic option available today that delivers those qualities.

Fluoros can be dimmed, as can CFLs, as can some discharge lighting, but not over anything like 0% - 100% without bumps. Few LEDs have either the dimming qualities or the colour rendering qualities, and those that do are very expensive.

If they can use fluorescent 90% of the time and dimmed incandescents for the other 10% then they can save a shedload of money on running costs.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
110315-1329 EST

Incandescent lamp life is not all that bad if you reduce the applied voltage relative to the rated voltage.

Halogen are not suited to dimming if the intent is to make use of the halogen effect. This requires a minimum temperature inside the bulb.

For an ordinary incandescent lamp its life is about

Average life in hours at reduced voltage = Rated life * ( Rated Voltage / Reduced Voltage )^13.1
from http://www.zap-tek.com/webpage/Elect/lsn_4/014_lamp_res.html

If the applied voltage is 100 V to a lamp rated at 1000 hours at 120 V, then average predicted life is 1000*(120/100)^13.1 = 1000*10.9 = 10,900 hours. At lower voltages the life is longer.

The bigger problem is whether you can buy a regular incandescent in the future.

Using a lower voltage as the maximum relative to the bulb voltage rating means you need more bulbs to get the same light at maximum brightness as compared to operating at full line voltage.

Lamp life only gets better as you dim them.

If you use a soft start dimmer, if they are even made, would help increase lamp life under many on-off cycles.

.
 
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